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PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

pkg/sentry/kernel/memevent/BUILD

@@ -0,0 +1,31 @@
+package(licenses = ["notice"])  # Apache 2.0
+
+load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "memevent",
+    srcs = ["memory_events.go"],
+    importpath = "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/memevent",
+    visibility = ["//:sandbox"],
+    deps = [
+        ":memory_events_go_proto",
+        "//pkg/eventchannel",
+        "//pkg/log",
+        "//pkg/sentry/kernel",
+        "//pkg/sentry/usage",
+    ],
+)
+
+proto_library(
+    name = "memory_events_proto",
+    srcs = ["memory_events.proto"],
+    visibility = ["//visibility:public"],
+)
+
+go_proto_library(
+    name = "memory_events_go_proto",
+    importpath = "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/memevent/memory_events_go_proto",
+    proto = ":memory_events_proto",
+    visibility = ["//visibility:public"],
+)

pkg/sentry/kernel/memevent/memory_events.go

@@ -0,0 +1,98 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package memevent implements the memory usage events controller, which
+// periodically emits events via the eventchannel.
+package memevent
+
+import (
+	"sync"
+	"time"
+
+	"gvisor.googlesource.com/gvisor/pkg/eventchannel"
+	"gvisor.googlesource.com/gvisor/pkg/log"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	pb "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/memevent/memory_events_go_proto"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usage"
+)
+
+// MemoryEvents describes the configuration for the global memory event emitter.
+type MemoryEvents struct {
+	k *kernel.Kernel
+
+	// The period is how often to emit an event. The memory events goroutine
+	// will ensure a minimum of one event is emitted per this period, regardless
+	// how of much memory usage has changed.
+	period time.Duration
+
+	// Writing to this channel indicates the memory goroutine should stop.
+	stop chan struct{}
+
+	// done is used to signal when the memory event goroutine has exited.
+	done sync.WaitGroup
+}
+
+// New creates a new MemoryEvents.
+func New(k *kernel.Kernel, period time.Duration) *MemoryEvents {
+	return &MemoryEvents{
+		k:      k,
+		period: period,
+		stop:   make(chan struct{}),
+	}
+}
+
+// Stop stops the memory usage events emitter goroutine. Stop must not be called
+// concurrently with Start and may only be called once.
+func (m *MemoryEvents) Stop() {
+	close(m.stop)
+	m.done.Wait()
+}
+
+// Start starts the memory usage events emitter goroutine. Start must not be
+// called concurrently with Stop and may only be called once.
+func (m *MemoryEvents) Start() {
+	if m.period == 0 {
+		return
+	}
+	go m.run() // S/R-SAFE: doesn't interact with saved state.
+}
+
+func (m *MemoryEvents) run() {
+	m.done.Add(1)
+
+	ticker := time.NewTicker(m.period)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-m.stop:
+			m.done.Done()
+			return
+		case <-ticker.C:
+			m.emit()
+		}
+	}
+}
+
+func (m *MemoryEvents) emit() {
+	totalPlatform, err := m.k.Platform.Memory().TotalUsage()
+	if err != nil {
+		log.Warningf("Failed to fetch memory usage for memory events: %v", err)
+		return
+	}
+	snapshot, _ := usage.MemoryAccounting.Copy()
+	total := totalPlatform + snapshot.Mapped
+
+	eventchannel.Emit(&pb.MemoryUsageEvent{Total: total})
+}

pkg/sentry/kernel/memevent/memory_events.proto

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+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package gvisor;
+
+// MemoryUsageEvent describes the memory usage of the sandbox at a single
+// instant in time. These messages are emitted periodically on the eventchannel.
+message MemoryUsageEvent {
+  // The total memory usage of the sandboxed application in bytes, calculated
+  // using the 'fast' method.
+  uint64 total = 1;
+}